Comparison of GH3 Protein Binding Sites. In plants, GH3 proteins act as molecular on/off switches that control bioactive plant hormone formation by catalyzing the addition of specific amino acids to jasmonic acid, auxin, and benzoates. X-ray structures of GH3 proteins reveal a common three-dimensional fold but variability in the hormone binding site. This figure shows the variation in the jasmonic acid binding site of Arabidopsis thaliana GH3.11/JAR1 (gold) and the salicylic acid binding site of A. thaliana GH3.12/PBS3 (green). more...

Image credit: Argonne National Laboratory

Plants respond to developmental cues and environmental stresses by controlling both the level and activity of various hormones. A highly adaptable scaffold enables the evolution of promiscuous activity within the auxin-responsive GH3 enzyme family, leading to diversification of substrate specificity and evolution of metabolic control systems. Newly reported crystal structures provide a glimpse into substrate recognition and control of hormones involved in plant growth, development, and defense, enabling deeper understanding of plant metabolism intricacies. The research was conducted using resources at the Advanced Photon Source at Argonne National Laboratory.

Reference: Westfall, C. S., et al. 2012. “Structural Basis for Prereceptor Modulation of Plant Hormones by GH3 Proteins,” Science 336, 1708–11. (Reference link)

Contact: Roland F. Hirsch, SC-23.2, (301) 903-9009
Topic Areas:

• Research Area: Plant Systems and Feedstocks, Plant-Microbe Interactions
• Research Area: Structural Biology, Biomolecular Characterization and Imaging
• Research Area: Structural Biology Infrastructure

Division: SC-33.2 Biological Systems Science Division, BER